Preparation of secondary alkyl sulfate particles with improved solubility

ABSTRACT

Preparation of secondary (2,3) alkyl sulfate particles comprises admixing secondary (2,3) alkyl sulfate surfactants with a deagglomerating agent such as zeolite or silica. The resulting powder is agglomerated with a nonionic surfactant, and formed into particles. The particles are then coated with a free-flow aid. Secondary (2,3) alkyl sulfate particles treated in this manner have improved solubility characteristics for use in laundry detergents.

This application claims the benefit of U.S. Provisional Application No.60/013,309, filed Mar. 8, 1996.

FIELD OF THE INVENTION

Secondary alkyl sulfate (SAS) surfactants are processed using variousingredients to provide improved water solubility. The resulting SASparticles are useful in laundry detergents and other cleaningcompositions, especially under cold water washing conditions.

BACKGROUND OF THE INVENTION

Most conventional detergent compositions contain mixtures of variousdetersive surfactants in order to remove a wide variety of soils andstains from surfaces. For example, various anionic surfactants,especially the alkyl benzene sulfonates, are useful for removingparticulate soils, and various nonionic surfactants, such as the alkylethoxylates and alkylphenol ethoxylates, are useful for removing greasysoils. While a review of the literature would seem to suggest that awide selection of surfactants is available to the detergentmanufacturer, the reality is that many such materials are specialtychemicals which are not suitable for routine use in low unit cost itemssuch as home laundering compositions. The fact remains that manyhome-use laundry detergents still comprise one or more of theconventional alkyl benzene sulfonate or primary alkyl sulfatesurfactants.

One class of surfactants which has found limited use in variouscompositions where emulsification is desired comprises the secondaryalkyl sulfates. The conventional secondary alkyl sulfates are availableas generally pasty, random mixtures of sulfated linear and/or partiallybranched alkanes. Such materials have not come into widespread use inlaundry detergents, since they offer no particular advantages over thealkyl benzene sulfonates.

Modern granular laundry detergents are being formulated in "condensed"form which offers substantial advantages, both to the consumer and tothe manufacturer. For the consumer, the smaller package size attendantwith condensed products provides ease-of-handling and storage. For themanufacturer, unit storage costs, shipping costs and packaging costs arelowered.

The manufacture of acceptable condensed granular detergents is notwithout its difficulties. In a typical condensed formulation, theso-called "inert" ingredients such as sodium sulfate are mainly deleted.However, such ingredients do play a role in enhancing the solubility ofconventional spray-dried detergent; hence, the condensed form will oftensuffer from solubility problems. Moreover, conventional low-densitydetergent granules are usually prepared by spray-drying processes whichresult in porous detergent particles that are quite amenable to beingsolubilized in aqueous laundry liquors. By contrast, condensedformulations will typically comprise substantially less porous, highdensity detergent particles which are less amenable to solubilization.Overall, since the condensed form of granular detergents typicallycomprises particles which contain high levels of detersive ingredientswith little room for solubilizing agents, and since such particles areintentionally manufactured at high bulk densities, the net result can bea substantial problem with regard to in-use solubility.

It has now been discovered that a particular sub-set of the class ofsecondary alkyl sulfates, referred to herein as secondary (2,3) alkylsulfates ("SAS"), offers considerable advantages to the formulator anduser of detergent compositions. For example, the secondary (2,3) alkylsulfates are available as dry, particulate solids. Accordingly, theyprospectively can be formulated as high-surfactant (i.e., "high-active")particles for use in granular laundry detergents. Since, with propercare in manufacturing, the secondary (2,3) alkyl sulfates are availablein solid, particulate form, they can be dry-mixed into granulardetergent compositions without the need for passage through spray dryingtowers. In addition to the foregoing advantages seen for the secondary(2,3) alkyl sulfates, it has now been determined that they are bothaerobically and anaerobically degradable, which assists in theirdisposal in the environment. Desirably, the secondary (2,3) alkylsulfates are quite compatible with detersive enzymes, especially in thepresence of calcium ions.

Unfortunately, commercially available SAS particles are somewhatdeficient with regard to their rate of solubility in cooler aqueous washliquors. This problem is especially acute in countries where consumersprefer cold washing temperatures, i.e., as low as about 5° C. Thisproblem is further exacerbated when SAS is used in high densitydetergent granules.

The present invention converts commercial SAS powder which has arelatively slow dissolution rate into fast-dissolving detergentparticles. Importantly, the SAS particles provided herein arefree-flowing, and can be readily admixed with other ingredients toprovide fully-formulated granular detergents. Accordingly, the presentinvention overcomes many of the problems associated with the use of SASin granular laundry detergents or other granular cleaning compositions.

BACKGROUND ART

Detergent compositions with various "secondary" and branched alkylsulfates are disclosed in various patents; see: U.S. Pat. No. 2,900,346,Fowkes et al, Aug. 18, 1959; U.S. Pat. No. 3,234,258, Morris, Feb. 8,1966; U.S. Pat. No. 3,468,805, Grifo et al, Sep. 23, 1969; U.S. Pat. No.3,480,556, DeWitt et al, Nov. 25, 1969; U.S. Pat. No. 3,681,424, Blochet al, Aug. 1, 1972; U.S. Pat. No. 4,052,342, Fernley et al, Oct. 4,1977; U.S. Pat. No. 4,079,020, Mills et al, Mar. 14, 1978; U.S. Pat. No.4,226,797, Bakker et al., Oct. 7, 1980; U.S. Pat. No. 4,235,752, Rossallet al, Nov. 25, 1980; U.S. Pat. No. 4,317,938, Lutz, Mar. 2, 1982; U.S.Pat. No. 4,529,541, Wilms et al, Jul. 16, 1985; U.S. Pat. No. 4,614,612,Reilly et al, Sep. 30, 1986; U.S. Pat. No. 4,880,569, Leng et al, Nov.14, 1989; U.S. Pat. No. 5,075,041, Lutz, Dec. 24, 1991; U.S. Pat. No.5,349,101, Lutz et al., Sep. 20, 1994; U.S. Pat. No. 5,389,277, Prieto,Feb. 14, 1995; U.K. 818,367, Bataafsche Petroleum, Aug. 12, 1959; U.K.858,500, Shell, Jan. 11, 1961; U.K. 965,435, Shell, Jul. 29, 1964; U.K.1,538,747, Shell, Jan. 24, 1979; U.K. 1,546,127, Shell, May 16, 1979;U.K. 1,550,001, Shell, Aug. 8, 1979; U.K. 1,585,030, Shell, Feb. 18,1981; GB 2,179,054A, Leng et al, Feb. 25, 1987 (referring to GB2,155,031). U.S. Pat. No. 3,234,258, Morris, Feb. 8, 1966, relates tothe sulfation of alpha olefins using H₂ SO₄, an olefin reactant and alow boiling, nonionic, organic crystallization medium.

Various means and apparatus suitable for preparing high-density granuleshave been disclosed in the literature and some have been used in thedetergency art. See, for example: U.S. Pat. No. 5,133,924; EP-A-367,339;EP-A-390,251; EP-A-340,013; EP-A-327,963; EP-A-337,330; EP-B-229,671;EP-B2-191,396; JP-A-6,106,990; EP-A-342,043; GB-B-2,221,695;EP-B-240,356; EP-B-242,138; EP-A-242,141; U.S. Pat. No. 4,846,409;EP-A-420,317; U.S. Pat. No. 2,306,698; EP-A-264,049; U.S. Pat. No.4,238,199; DE 4,021,476.

See also: WO 94/24238; WO 94/24239; WO 94/24240; WO 94/24241; WO94/24242; WO 94/24243; WO 94/24244; WO 94/24245; WO 94/24246; U.S. Pat.No. 5,478,500, Swift et al, Dec. 26, 1995; U.S. Pat. No. 5,478,502,Swift, Dec. 26, 1995;U.S. Pat. No. 5,478,503, Dec. 26, 1995.

SUMMARY OF THE INVENTION

The present invention encompasses a process for preparing particles ofsecondary (2,3) alkyl sulfate surfactants with improved solubility,comprising the steps of:

(a) admixing said secondary (2,3) alkyl sulfate in particulate form witha de-agglomerating agent to provide a substantially homogeneous powdermixture containing at least about 75%, preferably about 75% to about90%, by weight, of said secondary (2,3) alkyl sulfate;

(b) admixing a binding agent which is a nonionic surfactant with thepowder mixture from step (a) to form agglomerates;

(c) admixing additional de-agglomerating agent to the agglomerates ofstep (b) until the size of said agglomerates is reduced to providefree-flowing particles in the mean size range of about 100 to 2000micrometers;

(d) coating the particles of step (c) with a free-flow aid; and

(e) optionally, sizing the coated particles of step (d) to a meanparticle size in the preferred range from about 100 to about 1500micrometers.

The preferred deagglomerating agent in step (a) is a member selectedfrom the group consisting of zeolites, silica, water-insoluble layeredsilicate (e.g., SKS-6), and mixtures thereof The preferred weight ratioof secondary (2,3) alkyl sulfate: deagglomerating agent in step (a) isin the range from about 80:20 to about 99.5:0.5.

In step (b), the preferred weight ratio of secondary (2,3) alkyl sulfateto nonionic surfactant is in the range from about 90:10 to about 75:25.Preferred nonionic surfactants used in this step comprise the alcoholethoxylates, especially the C₁₀ -C₁₈ EO (3-10) ethoxylates, mostpreferably the C₁₄ -C₁₅ alcohol ethoxylates with an average EO of about7.

The free-flow aid used in step (d) is preferably a member selected fromthe group consisting of finely powdered (0.5-10 micrometer) zeolite,finely powdered silica and mixtures thereof. Most preferably, theparticles prepared in step (d) comprise from about 5% to about 25%, byweight, of total zeolite and from about 0% to about 20%, by weight, oftotal silica.

The invention also provides fully-formulated granular detergentcompositions, comprising conventional formulation ingredients and atleast about 5%, by weight, of the particles prepared according to theprocess herein, more preferably from about 10% to about 99%, by weight,of the particles prepared with the nonionic plus free-flow aid coatingnoted above.

All percentages, ratios and proportions herein are by weight, unlessotherwise specified. All documents cited are, in relevant part,incorporated herein by reference.

DETAILED DESCRIPTION OF THE INVENTION

The SAS surfactant and its processing in the manner of the presentinvention are described in detail, hereinafter. Other ingredients whichcan be used to prepare fully-formulated detergent compositions are alsodisclosed for the convenience of the formulator, but are not intended tobe limiting thereof.

Secondary (2,3) Alkyl Sulfate Surfactant

The soluble particles provided by the process herein preferably containfrom about 10% to about 70%, more preferably from about 20% to about60%, and most preferably from about 30% to about 50% of a secondary(2,3) alkyl sulfate surfactant as described herein. For the convenienceof those skilled in the art, the following discussion of the secondary(2,3) alkyl sulfates used herein serves to distinguish these materialsfrom conventional alkyl sulfate ("AS") surfactants.

The discovery that SAS powder can be processed by various grinding andcoating techniques is very surprising and unexpected, and suggests thatthis is unique for SAS. SAS powder is highly crystalline, and thus veryfriable and easily broken into fine dust without unduestickiness/reagglomeration. Once treated in the manner of thisinvention, this fine dust of SAS can be dispersed in water to givefaster dissolution due to the increased surface area.

In contrast, normal surfactants, due to impurities and chain lengthmixtures, are not friable enough to be easily broken, and do not lend tosuch processing methods. The conventional AS surfactants constitute onesuch example. Although pure AS is highly crystalline, the commercialgrade of AS is present as AS crystals dispersed in a waxy medium ofimpurities. Grinding is not possible at normal temperatures. Since theAS crystals have larger particle sizes than the ground SAS, AS also doesnot disperse as well in water, and AS particles suffer from a relativelyslower dissolution rate.

Conventional primary alkyl sulfate surfactants have the general formula

    ROSO.sub.3 --M.sup.+

wherein R is typically a linear C₁₀ -C₂₀ hydrocarbyl group and M is awater-solubilizing cation. Branched-chain primary alkyl sulfatesurfactants (i.e., branched-chain "PAS") having 10-20 carbon atoms arealso known; see, for example, European Patent Application 439,316, Smithet al, filed 21.01.91.

Conventional secondary alkyl sulfate surfactants are those materialswhich have the sulfate moiety distributed randomly along the hydrocarbyl"backbone" of the molecule. Such materials may be depicted by thestructure

    CH.sub.3 (CH.sub.2).sub.n (CHOSO.sub.3 --M.sup.+)(CH.sub.2).sub.m CH.sub.3

wherein m and n are integers of 2 or greater and the sum of m+n istypically about 9 to 17, and M is a water-solubilizing cation.

By contrast with the above, the selected secondary (2,3) alkyl sulfatesurfactants used herein comprise structures of formulas A and B

(A) CH₃ (CH₂)_(x) (CHOSO₃ --M⁺)CH₃ and

(B) CH₃ (CH₂)_(y) (CHOSO₃ --M⁺)CH₂ CH₃

for the 2-sulfate and 3-sulfate, respectively. Mixtures of the 2- and3-sulfate can be used herein. In formulas A and B, x and (y+1) are,respectively, integers of at least about 6, and can range from about 7to about 20, preferably about 10 to about 16. M is a cation, such as analkali metal, ammonium, alkanolammonium, alkaline earth metal, or thelike. Sodium is typical for use as M to prepare the water-solublesecondary (2,3) alkyl sulfates, but ethanolammonium, diethanolammonium,triethanolammonium, potassium, ammonium, and the like, can also be used.Materials A and B, and mixtures thereof, are abbreviated "SAS", herein.

By the present invention, it has been determined that thephysical/chemical properties of the foregoing types of alkyl sulfatesurfactants are unexpectedly different, one from another, in severalaspects which are important to formulators of various types of detergentcompositions. For example, the primary alkyl sulfates candisadvantageously interact with, and even be precipitated by, metalcations such as calcium and magnesium. Thus, water hardness cannegatively affect the primary alkyl sulfates to a greater extent thanSAS. Accordingly, the SAS has now been found to be preferred for use inthe presence of calcium ions and under conditions of high waterhardness, or in the so-called "under-built" situation which can occurwhen nonphosphate builders are employed.

With regard to the random secondary alkyl sulfates (i.e., secondaryalkyl sulfates with the sulfate group at positions such as the 4, 5, 6,7, etc. secondary carbon atoms), such materials tend to be tacky solidsor, more generally, pastes. Thus, the random alkyl sulfates do notafford the processing advantages associated with the solid SAS whenformulating detergent granules. Moreover, SAS provides better sudsingthan the random mixtures. It is preferred that SAS be substantially free(i.e., contain less than about 20%, more preferably less than about 10%,most preferably less than about 5%) of such random secondary alkylsulfates.

One additional advantage of the SAS surfactants herein over otherpositional or "random" alkyl sulfate isomers is in regard to theimproved benefits afforded by said SAS with respect to soil redepositionin the context of fabric laundering operations. As is well-known tousers, laundry detergents loosen soils from fabrics being washed andsuspend the soils in the aqueous laundry liquor. However, as iswell-known to detergent formulators, some portion of the suspended soilcan be redeposited back onto the fabrics. Thus, some redistribution andredeposition of the soil onto all fabrics in the load being washed canoccur. This, of course, is undesirable and can lead to the phenomenonknown as fabric "graying". (As a simple test of the redepositioncharacteristics of any given laundry detergent formulation, unsoiledwhite "tracer" cloths can be included with the soiled fabrics beinglaundered. At the end of the laundering operation the extent to whichthe white tracers deviate from their initial degree of whiteness can bemeasured photometrically or estimated visually by skilled observers. Themore the tracers' whiteness is retained, the less soil redeposition hasoccurred.)

It has also been determined that SAS affords substantial advantages insoil redeposition characteristics over the other positional isomers ofsecondary alkyl sulfates in laundry detergents, as measured by the clothtracer method noted above. Thus, the selection of SAS surfactantsaccording to the practice of this invention which preferably aresubstantially free of other positional secondary isomers unexpectedlyassists in solving the problem of soil redeposition in a manner notheretofore recognized.

It is to be noted that the SAS used herein is quite different in severalimportant properties from the secondary olefin sulfonates (e.g., U.S.Pat. No. 4,064,076, Klisch et al, Dec. 20, 1977); accordingly, suchsecondary sulfonates are not the focus of the present invention.

The preparation of SAS of the type useful herein can be carried out bythe addition of H₂ SO₄ to olefins. A typical synthesis using α-olefinsand sulfuric acid is disclosed in U.S. Pat. No. 3,234,258, Morris, or inU.S. Pat. No. 5,075,041, Lutz, granted Dec. 24, 1991, both of which areincorporated herein by reference. The synthesis, conducted in solventswhich afford the SAS on cooling, yields products which, when purified toremove the unreacted materials, randomly sulfated materials, unsulfatedby-products such as C₁₀ and higher alcohols, secondary olefinsulfonates, and the like, are typically 90+% pure mixtures of 2- and3-sulfated materials (up to 10% sodium sulfate is typically present) andare white, non-tacky, apparently crystalline, solids. Some2,3-disulfates may also be present, but generally comprise no more than5% of the mixture of secondary (2,3) alkyl mono-sulfates.

If still further increases in the solubility of the "crystalline" SASsurfactants are desired, the formulator may wish to employ mixtures ofsuch surfactants having a mixture of alkyl chain lengths. Thus, amixture of C₁₂ -C₁₈ alkyl chains will provide an increase in solubilityover an SAS wherein the alkyl chain is, say, entirely C₁₆. Thisadditional increase in solubility is in addition to the increaseprovided by the processing aspects of the present invention.

When formulating detergent compositions using the soluble particlesprovided by this invention, it may be desirable that the SAS surfactantscontain less than about 3% sodium sulfate, preferably less than about 1%sodium sulfate. In and of itself, sodium sulfate is an innocuousmaterial. However, it provides no cleaning function in the compositionsand may constitute a load on the system when dense granules are beingformulated.

Various means can be used to lower the sodium sulfate content of theSAS. For example, when the H₂ SO₄ addition to the olefin is completed,care can be taken to remove unreacted H₂ SO₄ before the acid form of theSAS is neutralized. In another method, the sodium salt form of the SASwhich contains sodium sulfate can be rinsed with water at a temperaturenear or below the Krafft temperature of the sodium SAS. This will removeNa₂ SO₄ with only minimal loss of the desired, purified sodium SAS. Ofcourse, both procedures can be used, the first as a pre-neutralizationstep and the second as a post-neutralization step.

The term "Krafft temperature" as used herein is a term of art which iswell-known to workers in the field of surfactant sciences. Kraffttemperature is described by K. Shinoda in the text "Principles ofSolution and Solubility", translation in collaboration with Paul Becher,published by Marcel Dekker, Inc. 1978 at pages 160-161. Statedsuccinctly, the solubility of a surface active agent in water increasesrather slowly with temperature up to that point, i.e., the Kraffttemperature, at which the solubility evidences an extremely rapid rise.At a temperature approximately 4° C. above the Krafft temperature asolution of almost any composition becomes a homogeneous phase. Ingeneral, the Krafft temperature of any given type of surfactant, such asthe SAS herein which comprises an anionic hydrophilic sulfate group anda hydrophobic hydrocarbyl group, will vary with the chain length of thehydrocarbyl group. This is due to the change in water solubility withthe variation in the hydrophobic portion of the surfactant molecule.

The formulator may optionally wash the SAS surfactant which iscontaminated with sodium sulfate with water at a temperature that is nohigher than the Krafft temperature, and which is preferably lower thanthe Krafft temperature, for the particular SAS being washed. This allowsthe sodium sulfate to be dissolved and removed with the wash water,while keeping losses of the SAS into the wash water to a minimum.

Under circumstances where the SAS surfactant herein comprises a mixtureof alkyl chain lengths, it will be appreciated that the Kraffttemperature will not be a single point but, rather, will be denoted as a"Krafft boundary". Such matters are well-known to those skilled in thescience of surfactant/solution measurements. In any event, for suchmixtures of SAS, it is preferred to conduct the optional sodium sulfateremoval operation at a temperature which is below the Krafft boundary,and preferably below the Krafft temperature of the shortest chain-lengthsurfactant present in such mixtures, since this avoids excessive lossesof SAS to the wash solution. For example, for C₁₆ secondary sodium alkyl(2,3) sulfate surfactants, it is preferred to conduct the washingoperation at temperatures below about 30° C., preferably below about 20°C. It will be appreciated that changes in the cations will change thepreferred temperatures for washing the SAS surfactants, due to changesin the Krafft temperature.

The washing process can be conducted batchwise by suspending wet or drySAS in sufficient water to provide 10-50% solids, typically for a mixingtime of at least 10 minutes at about 22° C. (for a C₁₆ SAS), followed bypressure filtration. In a preferred mode, the slurry will comprisesomewhat less than 35% solids, inasmuch as such slurries arefree-flowing and amenable to agitation during the washing process. As anadditional benefit, the washing process also reduces the levels oforganic contaminants which comprise the random secondary alkyl sulfatesnoted above.

SAS Processing

On a pilot plant or commercial scale, the SAS particle manufacture inthe manner of this invention can be conducted using various pieces ofcommercial equipment, including such items as rotary mixers, grinders,compactors, spray-dry equipment, kneaders, blenders, extruders, and thelike, which are within the scope of conventional chemical engineeringprocesses. An important advantage of the present process is that itemploys equipment and ingredients which are otherwise well-known andconventional to those familiar with the manufacture of detergentcompositions to provide SAS particles with improved solubility. Forexample, the materials such as the zeolite or powdered silica used inStep (a) of the process are substantially the same as the zeolites andsilica listed herein under Formulation Ingredients. Likewise, thebinding agent materials used in Step (b) can also include otherconventional nonionic surfactants such as the Neodols®, the Dobanols®,the polyhydroxy fatty acid amides, the alkyl polyglycosides, and thelike, as well as polyethyleneglycol (PEG), as noted hereinafter. Thesame is true for other ingredients used in subsequent steps of theprocess. The following illustrates a preferred process herein, but isnot intended to limit the scope of the present invention.

In one convenient mode, the present process produces highly solubleSAS/nonionic agglomerates using a Lodige KM 50L batch type mixer.

Step (a)--The SAS powder (more than one chain length stocks may bemixed) and de-agglomerating agents (Zeolite A or water insoluble layeredsilicate with particle sizes of 0.5 to 10 micrometers, or powderedsilica with the same particle size range) are charged into a LodigeMixer (KM-Series) and mixed well (ca. 1-2 minutes) at 185 rpm and 3600rpm blade and chopper speeds, respectively, until there are no visiblelumps of SAS particles. The weight ratio of SAS to de-agglomeratingagent is about 80/20 to about 99.5/0.5.

Step (b)--A binding agent, e.g., hot nonionic surfactant such as C₁₄₋₁₅alcohol ethoxylate with 7 EO ("C45AE7"), heated at 30-70° C., is sprayedonto the well mixed powder of Step (a) in the same mixer now running atthe maximum speeds for both blade and chopper until coarse agglomeratesare formed (about 2-8 minutes). The ratio of total SAS to nonionicsurfactant in this agglomerate is about 90/10 to about 75/25.

Step (c)--Additional zeolite and/or powdered silica is charged onto theagglomerate from Step (b) in the same mixer. This addition is repeatedseveral times until the particles reach a free flowing state. The bladespeed is then reduced to 60-120 rpm while keeping the chopper speed atabout 3600 rpm to reduce the particle size further.

Step (d)--The mixer speed is then reduced to gentle mixing whileadditional zeolite and/or powdered silica powder is charged into themixer to coat the particles. This gentle mixing is continued until freezeolite (or silica) is not observed. The total level of zeolite in thefinal agglomerate is about 5-25% by weight. The total level of silicapowder in the final agglomerate is around 0-20% by weight.

Step (e)--After sizing through a 1.7 mm sieve, the SAS particle is nowready to be blended with the other parts of the detergent formula. Theseinclude other surfactant particles, additive particles, enzyme, bleach,bleach activator particles, etc.

Optionally, slurries of polymers (polyacrylate or copolymers), soilrelease polymers, dye transfer inhibitors, and brighteners can be addedduring Step (a). Powdered polymers and soil release polymers can also beadded in Step (a). Liquid solutions of dye transfer inhibitors can besprayed onto the mixing powders during Step (a). Powdered brightenerscan be converted into a pre-mix with the nonionic surfactant beforespraying the mixture in Step (b). Optionally, a vertical mixer FukaeHi-speed mixer 11L) can also be used to produce the SAS particlesagglomerate in the same manner.

Dissolution of the SAS particles prepared in the manner of thisinvention can be assessed by any convenient means, without undueexperimentation. For example, the SAS particles can be placed in waterfor incremental periods of time, and their rate of dissolution measuredby titrating the amount of dissolved SAS.

In a practical method which approximates what might be seen by theconsumer, the deposition of undissolved SAS particles on fabric ismeasured. In this method, the SAS particles are first riffled to ensuresample homogeneity. 1.5 grams of the particles are weighed out. Analiquot of water (typically, 1 liter of medium hardness city water) isequilibrated at any desired test temperature (conveniently roomtemperature ca. 20° C.). The SAS particles are added to a Terg-O-Tometerfirst before pouring in the one liter water. Four to five samples can berun in the same run.

The SAS particles are agitated for 10 minutes at 50 rpm in theTerg-O-Tometer. At the end of agitation period, the entire contents arepoured onto a 90 mm Buchner funnel covered with a black test fabric,"C70", available from EMC, using standard suction filtration by wateraspirator vacuum. The Terg-O-Tometer is rinsed with 500 ml of additionalwater with the same hardness and temperature and poured through thefabric on the Buchner funnel.

After filtration, the black fabric is dried in an oven with a setting of49° C. to 60° C. The appearance of the fabric is then visually graded ona 1-10 scale, 10 being the worst, i.e., with the most insoluble SASparticles on the fabric, while a grade of 1 is the best.

If desired, a confirming test can be run. In this test, the solutionfrom the Terg-O-Tometer is filtered through a 1 micron cellulose filterwith vacuum. The resulting solution is then titrated for anionicsurfactant concentration, using the industry standard 2-phase,Hyamine®/mixed indicator method. Hyamine is available from SigmaChemical Company.

In an alternate mode, the so-called "cat-SO₃ " titration method can beused. In this technique, samples of the aqueous laundering liquorcontaining the SAS (or fully-formulated SAS detergent composition) canbe taken after one minute and filtered with 0.45 mm nylon filter HPLC,after which the filtered solution is titrated with Hyamine in thepresence of anionic indicator dyes, as noted above. The amount of SASdissolved in the aqueous liquor is thereby determined.

SAS particles prepared by the process of the present invention exhibitimproved solubility, i.e., a 10 minute solubility in water which istypically about 4× to about 6× greater than unprocessed SAS particles,especially at cold (ca. 5° C.) or cool (15° C.-45° C.) washtemperatures. Said another way, the SAS particles herein are at leastabout 70%, typically from about 90% to about 100%, dissolved in cool orcold water in about 10 minutes, as compared with unprocessed SASparticles which are only about 20%-30% dissolved under the sameconditions.

Formulation Ingredients

The fully-formulated granular detergent compositions which are preparedusing the SAS particles of this invention will typically comprisevarious other formulation ingredients to provide auxiliary cleaning andfabric care benefits, aesthetic benefits and processing aids. Thefollowing are non-limiting examples of such ingredients which aretypical for use in the commercial practice of the present invention,especially to provide high quality fabric laundry detergentcompositions.

Builders--Detergent builders can optionally be included in thecompositions herein to assist in controlling mineral hardness. Inorganicas well as organic builders can be used. Builders are typically used infabric laundering compositions to assist in the removal of particulatesoils.

The level of builder can vary widely depending upon the end use of thecomposition and its desired physical form. When present, thecompositions will typically comprise at least about 1% builder. Granularformulations typically comprise from about 10% to about 80%, moretypically from about 15% to about 50% by weight, of the detergentbuilder. Lower or higher levels of builder, however, are not meant to beexcluded.

Inorganic or P-containing detergent builders include, but are notlimited to, the alkali metal, ammonium and alkanolammonium salts ofpolyphosphates (exemplified by the tripolyphosphates, pyrophosphates,and glassy polymeric metaphosphates), phosphonates, phytic acid,silicates, carbonates (including bicarbonates and sesquicarbonates),sulphates, and aluminosilicates. However, non-phosphate builders arerequired in some locales. Importantly, the compositions herein functionsurprisingly well even in the presence of the so-called "weak" builders(as compared with phosphates) such as citrate, or in the so-called"underbuilt" situation that may occur with zeolite or layered silicatebuilders.

Examples of silicate builders are the alkali metal silicates,particularly those having a SiO₂ :Na₂ O ratio in the range 1.6:1 to3.2:1 and layered silicates, such as the layered sodium silicatesdescribed in U.S. Pat. No. 4,664,839, issued May 12, 1987 to H. P.Rieck. NaSKS-6 is the trademark for a crystalline layered silicatemarketed by Hoechst (commonly abbreviated herein as "SKS-6"). Unlikezeolite builders, the Na SKS-6 silicate builder does not containaluminum. NaSKS-6 has the delta-Na₂ SiO₅ morphology form of layeredsilicate. It can be prepared by methods such as those described inGerman DE-A-3,417,649 and DE-A-3,742,043. SKS-6 is a highly preferredlayered silicate for use herein, but other such layered silicates, suchas those having the general formula NaMSi_(x) O_(2x+1).yH₂ O wherein Mis sodium or hydrogen, x is a number from 1.9 to 4, preferably 2, and yis a number from 0 to 20, preferably 0 can be used herein. Various otherlayered silicates from Hoechst include NaSKS-5, NaSKS-7 and NaSKS-11, asthe alpha, beta and gamma forms. As noted above, the delta-Na₂ SiO₅(NaSKS-6 form) is most preferred for use herein. Other silicates mayalso be useful such as for example magnesium silicate, which can serveas a crispening agent in granular formulations, as a stabilizing agentfor oxygen bleaches, and as a component of suds control systems.

Examples of carbonate builders are the alkaline earth and alkali metalcarbonates as disclosed in German Patent Application No. 2,321,001published on Nov. 15, 1973.

Aluminosilicate builders are useful in the present invention.Aluminosilical:e builders are of great importance in most currentlymarketed heavy duty granular detergent compositions. Aluminosilicatebuilders include those having the empirical formula:

    M.sub.z (zAlO.sub.2).sub.y !.xH.sub.2 O

wherein z and y are integers of at least 6, the molar ratio of z to y isin the range from 1.0 to about 0.5, and x is an integer from about 15 toabout 264.

Useful aluminosilicate ion exchange materials are commerciallyavailable. These aluminosilicates can be crystalline or amorphous instructure and can be naturally-occurring aluminosilicates orsynthetically derived. A method for producing aluminosilicate ionexchange materials is disclosed in U.S. Pat. No. 3,985,669, Krummel, etal, issued Oct. 12, 1976. Preferred synthetic crystallinealuminosilicate ion exchange materials useful herein are available underthe designations Zeolite A, Zeolite P (B), Zeolite MAP and Zeolite X. Inan especially preferred embodiment, the crystalline aluminosilicate ionexchange material has the formula:

    Na.sub.12  (AlO.sub.2).sub.12 (SiO.sub.2).sub.12 !.xH.sub.2 O

wherein x is from about 20 to about 30, especially about 27. Thismaterial is known as Zeolite A. Dehydrated zeolites (x=0-10) may also beused herein. Preferably, the aluminosilicate has a particle size ofabout 0.1-10 microns in diameter.

Organic detergent builders suitable for the purposes of the presentinvention include, but are not restricted to, a wide variety ofpolycarboxylate compounds. As used herein, "polycarboxylate" refers tocompounds having a plurality of carboxylate groups, preferably at least3 carboxylates. Polycarboxylate builder can generally be added to thecomposition in acid form, but can also be added in the form of aneutralized salt. When utilized in salt form, alkali metals, such assodium, potassium, and lithium, or alkanolammonium salts are preferred.

Included among the polycarboxylate builders are a variety of categoriesof useful materials. One important category of polycarboxylate buildersencompasses the ether polycarboxylates, including oxydisuccinate, asdisclosed in Berg, U.S. Pat. No. 3,128,287, issued Apr. 7, 1964, andLamberti et al, U.S. Pat. No. 3,635,830, issued Jan. 18, 1972. See also"TMS/TDS" builders of U.S. Pat. No. 4,663,071, issued to Bush et al, onMay 5, 1987. Suitable ether polycarboxylates also include cycliccompounds, particularly alicyclic compounds, such as those described inU.S. Pat. Nos. 3,923,679; 3,835,163; 4,158,635; 4,120,874 and 4,102,903.

Other useful detergency builders include the etherhydroxypolycarboxylates, copolymers of maleic anhydride with ethylene orvinyl methyl ether, 1, 3, 5-trihydroxy benzene-2, 4, 6-trisulphonicacid, and carboxymethyloxysuccinic acid, the various alkali metal,ammonium and substituted ammonium salts of polyacetic acids such asethylenediamine tetraacetic acid and nitrilotriacetic acid ("NTA"), aswell as polycarboxylates such as mellitic acid, succinic acid,oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid,carboxymethyloxysuccinic acid, and soluble salts thereof.

Citrate builders can be used in granular compositions, especially incombination with zeolite and/or layered silicate builders.Oxydisuccinates are also especially useful in such compositions andcombinations.

Also suitable in the detergent compositions of the present invention arethe 3,3-dicarboxy4-oxa-1,6-hexanedioates and the related compoundsdisclosed in U.S. Pat. No. 4,566,984, Bush, issued Jan. 28, 1986. Usefulsuccinic acid builders include the C₅ -C₂₀ alkyl and alkenyl succinicacids and salts thereof. A particularly preferred compound of this typeis dodecenylsuccinic acid. Specific examples of succinate buildersinclude: laurylsuccinate, myristylsuccinate, palmitylsuccinate,2-dodecenylsuccinate (preferred), 2-pentadecenylsuccinate, and the like.Laurylsuccinates are the preferred builders of this group, and aredescribed in European Patent Application 86200690.5/0,200,263, publishedNov. 5, 1986.

Other suitable polycarboxylates are disclosed in U.S. Pat. No.4,144,226, Crutchfield et al, issued Mar. 13, 1979 and in U.S. Pat. No.3,308,067, Diehl, issued Mar. 7, 1967. See also Diehl U.S. Pat. No.3,723,322.

Fatty acids, e.g., C₁₂ -C₁₈ monocarboxylic acids, can also beincorporated into the compositions alone, or in combination with theaforesaid builders, especially citrate and/or the succinate builders, toprovide additional builder activity. Such use of fatty acids willgenerally result in a diminution of sudsing, which should be taken intoaccount by the formulator.

In situations where phosphorus-based builders can be used, andespecially in the formulation of bars used for hand-launderingoperations, the various alkali metal phosphates such as the well-knownsodium tripolyphosphates, sodium pyrophosphate and sodium orthophosphatecan be used. Phosphonate builders such asethane-1-hydroxy-1,1-diphosphonate and other known phosphonates (see,for example, U.S. Pat. Nos. 3,159,581; 3,213,030; 3,422,021; 3,400,148and 3,422,137) can also be used.

Enzymes--Enzymes can be included in the formulations herein for a widevariety of fabric laundering purposes, including removal ofprotein-based, carbohydrate-based, or triglyceride-based stains, forexample, and for the prevention of fugitive dye transfer, and for fabricrestoration. Such enzymes include proteases, amylases, lipases,cellulases, and peroxidases, as well as mixtures thereof. Other types ofenzymes may also be included. They may be of any suitable origin, suchas vegetable, animal, bacterial, fungal and yeast origin. However, theirchoice is governed by several factors such as pH-activity and/orstability optima, thermostability, stability versus active detergents,builders and so on. In this respect bacterial or fungal enzymes arepreferred, such as bacterial amylases and proteases, and fungalcellulases.

Enzymes are normally incorporated at levels sufficient to provide up toabout 5 mg by weight, more typically about 0.01 mg to about 3 mg, ofactive enzyme per gram of the composition. Stated otherwise, thecompositions herein will typically comprise from about 0.001% to about5%, preferably 0.01%-3% by weight of a commercial enzyme preparation.Protease enzymes are usually present in such commercial preparations atlevels sufficient to provide from 0.005 to 0.1 Anson units (AU) ofactivity per gram of composition.

Suitable examples of proteases are the subtilisins which are obtainedfrom particular strains of B. subtilis and B. licheniforms. Anothersuitable protease is obtained from a strain of Bacillus, having maximumactivity throughout the pH range of 8-12, developed and sold by NovoIndustries A/S under the registered trade name ESPERASE. The preparationof this enzyme and analogous enzymes is described in British PatentSpecification No. 1,243,784 of Novo. Proteolytic enzymes suitable forremoving protein-based stains that are commercially available includethose solid under the tradenames ALCALASE and SAVINASE by NovoIndustries A/S (Denmark) and MAXATASE by International Bio-Synthetics,Inc. (The Netherlands). Other proteases include Protease A (see EuropeanPatent Application 130,756, published Jan. 9, 1985) and Protease B (seeEuropean Patent Application Serial No. 87303761.8, filed Apr. 28, 1987,and European Patent Application 130,756, Bott et al, published Jan. 9,1985).

Amylases include, for example, α-amylases described in British PatentSpecification No. 1,296,839 (Novo), RAPIDASE, InternationalBio-Synthetics, Inc. and TERMAMYL, Novo Industries.

The cellulase usable in the present invention include both bacterial orfungal cellulase. Preferably, they will have a pH optimum of between 5and 9.5. Suitable cellulases are disclosed in U.S. Pat. No. 4,435,307,Barbesgoard et al, issued Mar. 6, 1984, which discloses fungal cellulaseproduced from Humicola insolens and Humicola strain DSM1800 or acellulase 212-producing fungus belonging to the genus Aeromonas, andcellulase extracted from the hepatopancreas of a marine mollusk(Dolabella Auricula Solander). Suitable cellulases are also disclosed inGB-A-2.075.028; GB-A-2.095.275 and DE-OS-2.247.832. CAREZYME (Novo) isespecially useful.

Suitable lipase enzymes for detergent usage include those produced bymicroorganisms of the Pseudomonas group, such as Pseudomonas stutzeriATCC 19.154, as disclosed in British Patent 1,372,034. See also lipasesin Japanese Patent Application 53,20487, laid open to public inspectionon Feb. 24, 1978. This lipase is available from Amano Pharmaceutical Co.Ltd., Nagoya, Japan, under the trade name Lipase P "Amano," hereinafterreferred to as "Amano-P." Other commercial lipases include Amano-CES,lipases ex Chromobacter viscosum, e.g. Chromobacter viscosum var.lipolyticum NRRLB 3673, commercially available from Toyo Jozo Co.,Tagata, Japan; and further Chromobacter viscosum lipases from U.S.Biochemical Corp., U.S.A. and Disoynth Co., The Netherlands, and lipasesex Pseudomonas gladioli. The LIPOLASE enzyme derived from Humicolalanuginosa and commercially available from Novo (see also EPO 341,947)is a preferred lipase for use herein.

Peroxidase enzymes are used in combination with oxygen sources, e.g.,percarbonate, perborate, persulfate, hydrogen peroxide, etc. They areused for "solution bleaching," i.e. to prevent transfer of dyes orpigments removed from substrates during wash operations to othersubstrates in the wash solution. Peroxidase enzymes are known in theart, and include, for example, horseradish peroxidase, ligninase, andhaloperoxidase such as chloro- and bromo-peroxidase.Peroxidase-containing detergent compositions are disclosed, for example,in PCT International Application WO 89/099813, published Oct. 19, 1989,by O. Kirk, assigned to Novo Industries A/S.

A wide range of enzyme materials and means for their incorporation intosynthetic detergent compositions are also disclosed in U.S. Pat. No.3,553,139, issued Jan. 5, 1971 to McCarty et al. Enzymes are furtherdisclosed in U.S. Pat. No. 4,101,457, Place et al, issued Jul. 18, 1978,and in U.S. Pat. No. 4,507,219, Hughes, issued Mar. 26, 1985, both.Enzyme materials useful for detergent formulations, and theirincorporation into such formulations, are disclosed in U.S. Pat. No.4,261,868, Hora et al, issued Apr. 14, 1981. Enzymes for use indetergents can be stabilized by various techniques. Enzyme stabilizationtechniques are disclosed and exemplified in U.S. Pat. No. 3,600,319,issued Aug. 17, 1971 to Gedge, et al, and European Patent ApplicationPublication No. 0 199 405, Application No. 86200586.5, published Oct.29, 1986, Venegas. Enzyme stabilization systems, are also described, forexample, in U.S. Pat. No. 3,519,570.

Enzyme Stabilizers--The enzymes employed herein may be stabilized by thepresence of water-soluble sources of calcium and/or magnesium ions inthe finished compositions which provide such ions to the enzymes.(Calcium ions are generally somewhat more effective than magnesium ionsand are preferred herein if only one type of cation is being used.)Additional stability can be provided by the presence of various otherart-disclosed stabilizers, especially borate species: see Severson, U.S.Pat. No. 4,537,706. Typical detergents will comprise from about 1 toabout 30, preferably from about 2 to about 20, more preferably fromabout 5 to about 15, and most preferably from about 8 to about 12,millimoles of calcium ion per kg of finished composition. This can varysomewhat, depending on the amount of enzyme present and its response tothe calcium or magnesium ions. The level of calcium or magnesium ionsshould be selected so that there is always some minimum level availablefor the enzyme, after allowing for complexation with builders, fattyacids, etc., in the composition. Any water-soluble calcium or magnesiumsalt can be used as the source of calcium or magnesium ions, including,but not limited to, calcium chloride, calcium sulfate, calcium malate,calcium maleate, calcium hydroxide, calcium formate, and calciumacetate, and the corresponding magnesium salts. A small amount ofcalcium ion, generally from about 0.05 to about 0.4 millimoles per kg,is often also present in the composition due to calcium in the enzymeslurry and formula water. In solid detergent compositions theformulation may include a sufficient quantity of a water-soluble calciumion source to provide such amounts in the laundry liquor. In thealternative, natural water hardness may suffice.

It is to be understood that the foregoing levels of calcium and/ormagnesium ions are sufficient to provide enzyme stability. More calciumand/or magnesium ions can be added to the compositions to provide anadditional measure of grease removal performance. Accordingly, as ageneral proposition the compositions herein will typically comprise fromabout 0.05% to about 2% by weight of a water-soluble source of calciumor magnesium ions, or both. The amount can vary, of course, with theamount and type of enzyme employed in the composition.

The compositions herein may also optionally, but preferably, containvarious additional stabilizers, especially borate-type stabilizers.Typically, such stabilizers will be used at levels in the compositionsfrom about 0.25% to about 10%, preferably from about 0.5% to about 5%,more preferably from about 0.75% to about 3%, by weight of boric acid orother borate compound capable of forming boric acid in the composition(calculated on the basis of boric acid). Boric acid is preferred,although other compounds such as boric oxide, borax and other alkalimetal borates (e.g., sodium ortho-, meta- and pyroborate, and sodiumpentaborate) are suitable. Substituted boric acids (e.g., phenylboronicacid, butane boronic acid, and p-bromo phenylboronic acid) can also beused in place of boric acid.

Bleaching Compounds--Bleaching Agents and Bleach Activators--Thedetergent compositions herein may optionally contain bleaching agents orbleaching compositions containing a bleaching agent and one or morebleach activators. When present, bleaching agents will typically be atlevels of from about 1% to about 30%, more typically from about 5% toabout 20%, of the detergent composition, especially for fabriclaundering. If present, the amount of bleach activators will typicallybe from about 0.1% to about 60%, more typically from about 0.5% to about40% of the bleaching composition comprising the bleachingagent-plus-bleach activator.

The bleaching agents used herein can be any of the bleaching agentsuseful for detergent compositions in textile cleaning, hard surfacecleaning, or other cleaning purposes that are now known or become known.These include oxygen bleaches as well as other bleaching agents.Perborate bleaches, e.g., sodium perborate (e.g., mono- ortetra-hydrate) can be used herein.

Another category of bleaching agent that can be used without restrictionencompasses percarboxylic acid bleaching agents and salts thereof.Suitable examples of this class of agents include magnesiummonoperoxyphthalate hexahydrate, the magnesium salt of metachloroperbenzoic acid, 4-nonylamino-4-oxoperoxybutyric acid anddiperoxydodecanedioic acid. Such bleaching agents are disclosed in U.S.Pat. No. 4,483,781, Hartman, issued Nov. 20, 1984, U.S. patentapplication Ser. No. 740,446, Burns et al, filed Jun. 3, 1985, EuropeanPatent Application 0,133,354, Banks et al, published Feb. 20, 1985, andU.S. Pat. No. 4,412,934, Chung et al, issued Nov. 1, 1983. Highlypreferred bleaching agents also include 6-nonylamino-6-oxoperoxycaproicacid as described in U.S. Pat. No. 4,634,551, issued Jan. 6, 1987 toBurns et al.

Peroxygen bleaching agents can also be used. Suitable peroxygenbleaching compounds include sodium carbonate peroxyhydrate andequivalent "percarbonate" bleaches, sodium pyrophosphate peroxyhydrate,urea peroxyhydrate, and sodium peroxide. Persulfate bleach (e.g., OXONE,manufactured commercially by DuPont) an also be used.

A preferred percarbonate bleach comprises dry particles having anaverage particle size in the range from about 500 micrometers to about1,000 micrometers, not more than about 10% by weight of said particlesbeing smaller than about 200 micrometers and not more than about 10% byweight of said particles being larger than about 1,250 micrometers.Optionally, the percarbonate can be coated with silicate, borate orwater-soluble surfactants. Percarbonate is available from variouscommercial sources such as FMC, Solvay and Tokai Denka.

Mixtures of bleaching agents can also be used.

Peroxygen bleaching agents, the perborates, the percarbonates, etc., arepreferably combined with bleach activators, which lead to the in situproduction in aqueous solution (i.e., during the washing process) of theperoxy acid corresponding to the bleach activator. Various nonlimitingexamples of activators are disclosed in U.S. Pat. No. 4,915,854, issuedApr. 10, 1990 to Mao et al, and U.S. Pat. No. 4,412,934. Thenonanoyloxybenzene sulfonate (NOBS) and tetraacetyl ethylene diamine(TAED) activators are typical, and mixtures thereof can also be used.See also U.S. Pat. No. 4,634,551 for other typical bleaches andactivators useful herein.

Highly preferred amido-derived bleach activators are those of theformulae:

    R.sup.1 N(R.sup.5)C(O)R.sup.2 C(O)L

or

    R.sup.1 C(O)N(R.sup.5)R.sup.2 C(O)L

wherein R¹ is an alkyl group containing from about 6 to about 12 carbonatoms, R² is an alkylene containing from 1 to about 6 carbon atoms, R⁵is H or alkyl, aryl, or alkaryl containing from about 1 to about 10carbon atoms, and L is any suitable leaving group. A leaving group isany group that is displaced from the bleach activator as a consequenceof the nucleophilic attack on the bleach activator by the perhydrolysisanion. A preferred leaving group is phenyl sulfonate.

Preferred examples of bleach activators of the above formulae include(6-octanamido-caproyl)oxybenzenesulfonate,(6-nonanamidocaproyl)oxybenzenesulfonate,(6-decanamido-caproyl)oxybenzenesulfonate, and mixtures thereof asdescribed in U.S. Pat. No. 4,634,551, incorporated herein by reference.

Another class of bleach activators comprises the benzoxazin-typeactivators disclosed by Hodge et al in U.S. Pat. No. 4,966,723, issuedOct. 30, 1990, incorporated herein by reference. A highly preferredactivator of the benzoxazin-type is: ##STR1##

Still another class of preferred bleach activators includes the acyllactam activators, especially acyl caprolactams and acyl valerolactamsof the formulae: ##STR2## wherein R⁶ is H or an alkyl, aryl, alkoxyaryl,or alkaryl group containing from 1 to about 12 carbon atoms. Highlypreferred lactam activators include benzoyl caprolactam, octanoylcaprolactam, 3,5,5-trimethylhexanoyl caprolactam, nonanoyl caprolactam,decanoyl caprolactam, undecenoyl caprolactam, benzoyl valerolactam,octanoyl valerolactam, decanoyl valerolactam, undecenoyl valerolactam,nonanoyl valerolactam, 3,5,5-trimethylhexanoyl valerolactam and mixturesthereof. See also U.S. Pat. No. 4,545,784, issued to Sanderson, Oct. 8,1985, incorporated herein by reference, which discloses acylcaprolactams, including benzoyl caprolactam, adsorbed into sodiumperborate.

Bleaching agents other than oxygen bleaching agents are also known inthe art and can be utilized herein. One type of non-oxygen bleachingagent of particular interest includes photoactivated bleaching agentssuch as the sulfonated zinc and/or aluminum phthalocyanines. See U.S.Pat. No. 4,033,718, issued Jul. 5, 1977 to Holcombe et al. If used,detergent compositions will typically contain from about 0.025% to about1.25%, by weight, of such bleaches, especially sulfonate zincphthalocyanine.

If desired, the bleaching compounds can be catalyzed by means of amanganese compound. Such compounds are well known in the art andinclude, for example, the manganese-based catalysts disclosed in U.S.Pat. No. 5,246,621, U.S. Pat. No. 5,244,594; U.S. Pat. No. 5,194,416;U.S. Pat. No. 5,114,606; and European Pat. App. Pub. Nos. 549,271A1,549,272A1, 544,440A2, and 544,490A1; Preferred examples of thesecatalysts include Mn^(IV) ₂ (u-O)₃(1,4,7-trimethyl-1,4,7-triazacyclononane)₂ (PF₆)₂, Mn^(III) ₂ (u-OAc)₂(u-OAc)₂ (1,4,7-trimethyl-1,4,7-triazacyclononane)₂ -(ClO₄)₂, Mn^(IV) ₄(u-O)₆ (1,4,7-triazacyclononane)₄ (ClO₄)₄, Mn^(III) Mn^(IV) ₄ (u-O)₁(u-OAc)₂ --(1,4,7-trimethyl-1,4,7-triazacyclononane)₂ (ClO₄)₃, Mn^(IV)(1,4,7-trimethyl-1,4,7-triazacyclononane)--(OCH₃)₃ (PF₆), and mixturesthereof. Other metal-based bleach catalysts include those disclosed inU.S. Pat. No. 4,430,243 and U.S. Pat. No. 5,114,611. The use ofmanganese with various complex ligands to enhance bleaching is alsoreported in the following U.S. Pat. Nos.: 4,728,455; 5,284,944;5,246,612; 5,256,779; 5,280,117; 5,274,147; 5,153,161; and 5,227,084.

As a practical matter, and not by way of limitation, the compositionsand processes herein can be adjusted to provide on the order of at leastone part per ten million of the active bleach catalyst species in theaqueous washing liquor, and will preferably provide from about 0.1 ppmto about 700 ppm, more preferably from about 1 ppm to about 500 ppm, ofthe catalyst species in the laundry liquor.

Polymeric Soil Release Agent--Any polymeric soil release agent known tothose skilled in the art can optionally be employed in the compositionsand processes of this invention. Polymeric soil release agents arecharacterized by having both hydrophilic segments, to hydrophilize thesurface of hydrophobic fibers, such as polyester and nylon, andhydrophobic segments, to deposit upon hydrophobic fibers and remainadhered thereto through completion of washing and rinsing cycles and,thus, serve as an anchor for the hydrophilic segments. This can enablestains occurring subsequent to treatment with the soil release agent tobe more easily cleaned in later washing procedures.

The polymeric soil release agents useful herein especially include thosesoil release agents having: (a) one or more nonionic hydrophilecomponents consisting of at least 2, or (ii) oxypropylene orpolyoxypropylene segments with a degr essentially of (i) polyoxyethylenesegments with a degree of polymerization oee of polymerization of from 2to 10, wherein said hydrophile segment does not encompass anyoxypropylene unit unless it is bonded to adjacent moieties at each endby ether linkages, or (iii) a mixture of oxyalkylene units comprisingoxyethylene and from 1 to about 30 oxypropylene units wherein saidmixture contains a sufficient amount of oxyethylene units such that thehydrophile component has hydrophilicity great enough to increase thehydrophilicity of conventional polyester synthetic fiber surfaces upondeposit of the soil release agent on such surface, said hydrophilesegments preferably comprising at least about 25% oxyethylene units andmore preferably, especially for such components having about 20 to 30oxypropylene units, at least about 50% oxyethylene units; or (b) one ormore hydrophobe components comprising (i) C₃ oxyalkylene terephthalatesegments, wherein, if said hydrophobe components also compriseoxyethylene terephthalate, the ratio of oxyethylene terephthalate:C₃oxyalkylene terephthalate units is about 2:1 or lower, (ii) C₄ -C₆alkylene or oxy C₄ -C₆ alkylene segments, or mixtures therein, (iii)poly (vinyl ester) segments, preferably polyvinyl acetate), having adegree of polymerization of at least 2, or (iv) C₁ -C₄ alkyl ether or C₄hydroxyalkyl ether substituents, or mixtures therein, wherein saidsubstituents are present in the form of C₁ -C₄ alkyl ether or C₄hydroxyalkyl ether cellulose derivatives, or mixtures therein, and suchcellulose derivatives are amphiphilic, whereby they have a sufficientlevel of C₁ -C₄ alkyl ether and/or C₄ hydroxyalkyl ether units todeposit upon conventional polyester synthetic fiber surfaces and retaina sufficient level of hydroxyls, once adhered to such conventionalsynthetic fiber surface, to increase fiber surface hydrophilicity, or acombination of (a) and (b).

Typically, the polyoxyethylene segments of (a)(i) will have a degree ofpolymerization of from about 200, although higher levels can be used,preferably from 3 to about 150, more preferably from 6 to about 100.Suitable oxy C₄ -C₆ alkylene hydrophobe segments include, but are notlimited to, end-caps of polymeric soil release agents such as MO₃S(CH₂)_(n) OCH₂ CH₂ O--, where M is sodium and, n is an integer from4-6, as disclosed in U.S. Pat. No. 4,721,580, issued Jan. 26, 1988 toGosselink.

Polymeric soil release agents useful in the present invention alsoinclude cellulosic derivatives such as hydroxyether cellulosic polymers,copolymeric blocks of ethylene terephthalate or propylene terephthalatewith polyethylene oxide or polypropylene oxide terephthalate, and thelike. Such agents are commercially available and include hydroxyethersof cellulose such as METHOCEL (Dow). Cellulosic soil release agents foruse herein also include those selected from the group consisting of C₁-C₄ alkyl and C₄ hydroxyalkyl cellulose; see U.S. Pat. No. 4,000,093,issued Dec. 28, 1976 to Nicol, et al.

Soil release agents characterized by poly(vinyl ester) hydrophobesegments include graft copolymers of poly(vinyl ester), e.g., C_(1-C) ₆vinyl esters, preferably poly(vinyl acetate) grafted onto polyalkyleneoxide backbones, such as polyethylene oxide backbones. See EuropeanPatent Application 0 219 048, published Apr. 22, 1987 by Kud, et al.Commercially available soil release agents of this kind include theSOKALAN type of material, e.g., SOKALAN HP-22, available from BASF (WestGermany).

One type of preferred soil release agent is a copolymer having randomblocks of ethylene terephthalate and polyethylene oxide (PEO)terephthalate. The molecular weight of this polymeric soil release agentis in the range of from about 25,000 to about 55,000. See U.S. Pat. No.3,959,230 to Hays, issued May 25, 1976 and U.S. Pat. No. 3,893,929 toBasadur issued Jul. 8, 1975.

Another preferred polymeric soil release agent is a polyester withrepeat units of ethylene terephthalate units contains 10-15% by weightof ethylene terephthalate units together with 90-80% by weight ofpolyoxyethylene terephthalate units, derived from a polyoxyethyleneglycol of average molecular weight 300-5,000. Examples of this polymerinclude the commercially available material ZELCON 5126 (from DuPont)and MILEASE T (from ICI). See also U.S. Pat. No. 4,702,857, issued Oct.27, 1987 to Gosselink.

Another preferred polymeric soil release agent is a sulfonated productof a substantially linear ester oligomer comprised of an oligomericester backbone of terephthaloyl and oxyalkyleneoxy repeat units andterminal moieties covalently attached to the backbone. These soilrelease agents are described fully in U.S. Pat. No. 4,968,451, issuedNov. 6, 1990 to J. J. Scheibel and E. P. Gosselink. Other suitablepolymeric soil release agents include the terephthalate polyesters ofU.S. Pat. No. 4,711,730, issued Dec. 8, 1987 to Gosselink et al, theanionic end-capped oligomeric esters of U.S. Pat. No. 4,721,580, issuedJan. 26, 1988 to Gosselink, and the block polyester oligomeric compoundsof U.S. Pat. No. 4,702,857, issued Oct. 27, 1987 to Gosselink.

Preferred polymeric soil release agents also include the soil releaseagents of U.S. Pat. No. 4,877,896, issued Oct. 31, 1989 to Maldonado etal, which discloses anionic, especially sulfoaroyl, end-cappedterephthalate esters.

Still another preferred soil release agent is an oligomer with repeatunits of terephthaloyl units, sulfoisoterephthaloyl units,oxyethyleneoxy and oxy-1,2-propylene units. The repeat units form thebackbone of the oligomer and are preferably terminated with modifiedisethionate end-caps. A particularly preferred soil release agent ofthis type comprises about one sulfoisophthaloyl unit, 5 terephthaloylunits, oxyethyleneoxy and oxy-1,2-propyleneoxy units in a ratio of fromabout 1.7 to about 1.8, and two end-cap units of sodium2-(2-hydroxyethoxy)-ethanesulfonate. Said soil release agent alsocomprises from about 0.5% to about 20%, by weight of the oligomer, of acrystalline-reducing stabilizer, preferably selected from the groupconsisting of xylene sulfonate, cumene sulfonate, toluene sulfonate, andmixtures thereof.

If utilized, soil release agents will generally comprise from about0.01% to about 10.0%, by weight, of the detergent compositions herein,typically from about 0.1% to about 5%, preferably from about 0.2% toabout 3.0%.

Dye Transfer Inhibiting Agents--The compositions of the presentinvention may also include one or more materials effective forinhibiting the transfer of dyes from one fabric to another during thecleaning process. Generally, such dye transfer inhibiting agents includepolyvinyl pyrrolidone polymers, polyamine N-oxide polymers, copolymersof N-vinylpyrrolidone and N-vinylimidazole, manganese phthalocyanine,peroxidases, and mixtures thereof. If used, these agents typicallycomprise from about 0.01% to about 10% by weight of the composition,preferably from about 0.01% to about 5%, and more preferably from about0.05% to about 2%.

More specifically, the polyamine N-oxide polymers preferred for useherein contain units having the following structural formula: R--A_(x)--P; wherein P is a polymerizable unit to which an N--O group can beattached or the N--O group can form part of the polymerizable unit orthe N--O group can be attached to both units; A is one of the followingstructures: --NC(O)--, --C(O)O--, --S--, --O--, --N═; x is 0 or 1, and Ris aliphatic, ethoxylated aliphatics, aromatics, heterocyclic oralicyclic groups or any combination thereof to which the nitrogen of theN--O group can be attached or the N--O group is part of these groups.Preferred polyamine N-oxides are those wherein R is a heterocyclic groupsuch as pyridine, pyrrole, imidazole, pyrrolidine, piperidine andderivatives thereof

The N--O group can be represented by the following general structures:##STR3## wherein R₁, R₂, R₃ are aliphatic, aromatic, heterocyclic oralicyclic groups or combinations thereof; x, y and z are 0 or 1; and thenitrogen of the N--O group can be attached or form part of any of theaforementioned groups. The amine oxide unit of the polyamine N-oxideshas a pKa<10, preferably pKa<7, more preferred pKa<6.

Any polymer backbone can be used as long as the amine oxide polymerformed is water-soluble and has dye transfer inhibiting properties.Examples of suitable polymeric backbones are polyvinyls, polyalkylenes,polyesters, polyethers, polyamide, polyimides, polyacrylates andmixtures thereof. These polymers include random or block copolymerswhere one monomer type is an amine N-oxide and the other monomer type isan N-oxide. The amine N-oxide polymers typically have a ratio of amineto the amine N-oxide of 10:1 to 1:1,000,000. However, the number ofamine oxide groups present in the polyamine oxide polymer can be variedby appropriate copolymerization or by an appropriate degree ofN-oxidation. The polyamine oxides can be obtained in almost any degreeof polymerization. Typically, the average molecular weight is within therange of 500 to 1,000,000; more preferred 1,000 to 500,000; mostpreferred 5,000 to 100,000. This preferred class of materials can bereferred to as "PVNO".

The most preferred polyamine N-oxide useful in the detergentcompositions herein is poly(4-vinylpyridine-N-oxide) which as an averagemolecular weight of about 50,000 and an amine to amine N-oxide ratio ofabout 1:4.

Copolymers of N-vinylpyrrolidone and N-vinylimidazole polymers (referredto as a class as "PVPVI") are also preferred for use herein. Preferablythe PVPVI has an average molecular weight range from 5,000 to 1,000,000,more preferably from 5,000 to 200,000, and most preferably from 10,000to 20,000. (The average molecular weight range is determined by lightscattering as described in Barth, et al., Chemical Analysis, Vol 113."Modern Methods of Polymer Characterization", the disclosures of whichare incorporated herein by reference.) The PVPVI copolymers typicallyhave a molar ratio of N-vinylimidazole to N-vinylpyrrolidone from 1:1 to0.2:1, more preferably from 0.8:1 to 0.3:1, most preferably from 0.6:1to 0.4:1. These copolymers can be either linear or branched.

The present invention compositions also may employ apolyvinylpyrrolidone ("PVP") having an average molecular weight of fromabout 5,000 to about 400,00), preferably from about 5,000 to about200,000, and more preferably from about 5,000 to about 50,000. PVP's areknown to persons skilled in the detergent field; see, for example,EP-A-262,897 and EP-A-256,696, incorporated herein by reference.Compositions containing PVP can also contain polyethylene glycol ("PEG")having an average molecular weight from about 500 to about 100,000,preferably from about 1,000 to about 10,000. Preferably, the ratio ofPEG to PVP on a ppm basis delivered in wash solutions is from about 2:1to about 50:1, and more preferably from about 3:1 to about 10:1.

The detergent compositions herein may also optionally contain from about0.005% to 5% by weight of certain types of hydrophilic opticalbrighteners which also provide a dye transfer inhibition action. Ifused, the compositions herein will preferably comprise from about 0.01%to 1% by weight of such optical brighteners.

The hydrophilic optical brighteners useful in the present invention arethose having the structural formula: ##STR4## wherein R₁ is selectedfrom anilino, N-2-bis-hydroxyethyl and NH-2-hydroxyethyl; R₂ is selectedfrom N-2-bis-hydroxyethyl, N-2-hydroxyethyl-N-methylamino, morphilino,chloro and amino; and M is a salt-forming cation such as sodium orpotassium.

When in the above formula, R₁ is anilino, R₂ is N-2-bis-hydroxyethyl andM is a cation such as sodium, the brightener is 4,4',-bis(4-anilino-6-N-2-bis-hydroxyethyl)-s-triazine-2-yl)amino!-2,2'-stilbenedisulfonicacid and disodium salt. This particular brightener species iscommercially marketed under the tradename Tinopal-UNPA-GX by Ciba-GeigyCorporation. Tinopal-UNPA-GX is the preferred hydrophilic opticalbrightener useful in the detergent compositions herein.

When in the above formula, R₁ is anilino, R₂ isN-2-hydroxyethyl-N-2-methylamino and M is a cation such as sodium, thebrightener is 4,4'-bis(4-anilino-6-(N-2-hydroxyethyl-N-methylamino)-s-triazine-2-yl)amino!2,2'-stilbenedisulfonicacid disodium salt. This particular brightener species is commerciallymarketed under the tradename Tinopal 5BM-GX by Ciba-Geigy Corporation.

When in the above formula, R₁ is anilino, R₂ is morphilino and M is acation such as sodium, the brightener is 4,4'-bis(4-anilino-6-morphilino-s-triazine-2-yl)amino!2,2'-stilbenedisulfonicacid, sodium salt. This particular brightener species is commerciallymarketed under the tradename Tinopal AMS-GX by Ciba Geigy Corporation.

The specific optical brightener species selected for use in the presentinvention provide especially effective dye transfer inhibitionperformance benefits when used in combination with the selectedpolymeric dye transfer inhibiting agents hereinbefore described. Thecombination of such selected polymeric materials (e.g., PVNO and/orPVPVI) with such selected optical brighteners (e.g., Tinopal UNPA-GX,Tinopal 5BM-GX and/or Tinopal AMS-GX) provides significantly better dyetransfer inhibition in aqueous wash solutions than does either of thesetwo detergent composition components when used alone. Without beingbound by theory, it is believed that such brighteners work this waybecause they have high affinity for fabrics in the wash solution andtherefore deposit relatively quick on these fabrics. The extent to whichbrighteners deposit on fabrics in the wash solution can be defined by aparameter called the "exhaustion coefficient". The exhaustioncoefficient is in general as the ratio of a) the brightener materialdeposited on fabric to b) the initial brightener concentration in thewash liquor. Brighteners with relatively high exhaustion coefficientsare the most suitable for inhibiting dye transfer in the context of thepresent invention.

Of course, it will be appreciated that other, conventional opticalbrightener types of compounds can optionally be used in the presentcompositions to provide conventional fabric "brightness" benefits,rather than a true dye transfer inhibiting effect. Such usage isconventional and well-known to detergent formulations.

Chelating Agents--The detergent compositions herein may also optionallycontain one or more iron and/or manganese chelating agents. Suchchelating agents can be selected from the group consisting of aminocarboxylates, amino phosphonates, polyfunctionally-substituted aromaticchelating agents and mixtures therein, all as hereinafter defined.Without intending to be bound by theory, it is believed that the benefitof these materials is due in part to their exceptional ability to removeiron and manganese ions from washing solutions by formation of solublechelates.

Amino carboxylates useful as optional chelating agents includeethylenediaminetetracetates, N-hydroxyethylethylenediaminetriacetates,nitrilotriacetates, ethylenediamine tetraproprionates,triethylenetetraaminehexacetates, diethylenetrianiinepentaacetates(DTPA), and ethanoldiglycines, alkali metal, ammonium, and substitutedammonium salts therein and mixtures therein.

Amino phosphonates are also suitable for use as chelating agents in thecompositions of the invention when at least low levels of totalphosphorus are permitted in detergent compositions, and includeethylenediaminetetrakis (methylenephosphonates) as DEQUEST. Preferred,these amino phosphonates to not contain alkyl or alkenyl groups withmore than about 6 carbon atoms.

Polyfunctionally-substituted aromatic chelating agents are also usefulin the compositions herein. See U.S. Pat. No. 3,812,044, issued May 21,1974, to Connor et al. Preferred compounds of this type in acid form aredihydroxydisulfobenzenes such as 1,2-dihydroxy-3,5-disulfobenzene.

A preferred biodegradable chelator for use herein is ethylenediaminedisuccinate ("EDDS"), especially the S,S! isomer as described in U.S.Pat. No. 4,704,233, Nov. 3, 1987, to Hartman and Perkins.

If utilized, these chelating agents will generally comprise from about0.1% to about 10% by weight of the detergent compositions herein. Morepreferably, if utilized, the chelating agents will comprise from about0.1% to about 3.0% by weight of such compositions.

Clay Soil Removal/Anti-redeposition Agents--The compositions of thepresent invention can also optionally contain water-soluble ethoxylatedamines having clay soil removal and antiredeposition properties.Granular detergent compositions which contain these compounds typicallycontain from about 0.01% to about 10.0% by weight of the water-solubleethoxylates amines.

The most preferred soil release and anti-redeposition agent isethoxylated tetraethylenepentamine. Exemplary ethoxylated amines arefurther described in U.S. Pat. No. 4,597,898, VanderMeer, issued Jul. 1,1986. Another group of preferred clay soil removal-antiredepositionagents are the cationic compounds disclosed in European PatentApplication 111,965, Oh and Gosselink, published Jun. 27, 1984. Otherclay soil removal/antiredeposition agents which can be used include theethoxylated amine polymers disclosed in European Patent Application111,984, Gosselink, published Jun. 27, 1984; the zwitterionic polymersdisclosed in European Patent Application 112,592, Gosselink, publishedJul. 4, 1984; and the amine oxides, disclosed in U.S. Pat. No.4,548,744, Connor, issued Oct. 22, 1985. Other clay soil removal and/oranti redeposition agents known in the art can also be utilized in thecompositions herein. Another type of preferred antiredeposition agentincludes the carboxy methyl cellulose (CMC) materials. These materialsare well known in the art.

Suds Suppressors--Compounds for reducing or suppressing the formation ofsuds can be incorporated into the compositions of the present invention.Suds suppression can be of particular importance in the so-called "highconcentration cleaning process" as described in U.S. Pat. Nos. 4,489,455and 4,489,574 and in front-loading European-style washing machines.

A wide variety of materials may be used as suds suppressors, and sudssuppressors are well known to those skilled in the art. See, forexample, Kirk Othmer Encyclopedia of Chemical Technology, Third Edition,Volume 7, pages 430-447 (John Wiley & Sons, Inc., 1979). One category ofsuds suppressor of particular interest encompasses monocarboxylic fattyacid and soluble salts therein. See U.S. Pat. No. 2,954,347, issued Sep.27, 1960 to Wayne St. John. The monocarboxylic fatty acids and saltsthereof used as suds suppressor typically have hydrocarbyl chains of 10to about 24 carbon atoms, preferably 12 to 18 carbon atoms. Suitablesalts include the alkali metal salts such as sodium, potassium, andlithium salts, and ammonium and alkanolammonium salts.

The detergent compositions herein may also contain non-surfactant sudssuppressors. These include, for example: high molecular weighthydrocarbons such as paraffin, fatty acid esters (e.g., fatty acidtriglycerides), fatty acid esters of monovalent alcohols, aliphatic C₁₈-C₄₀ ketones (e.g., stearone), etc. Other suds inhibitors includeN-alkylated amino triazines such as tri- to hexa-alkylmelamines or di-to tetra-alkyldiamine chlortriazines formed as products of cyanuricchloride with two or three moles of a primary or secondary aminecontaining 1 to 24 carbon atoms, propylene oxide, and monostearylphosphates such as monostearyl alcohol phosphate ester and monostearyldi-alkali metal (e.g., K, Na, and Li) phosphates and phosphate esters.The hydrocarbons such as paraffin and haloparaffin can be utilized inliquid form. The liquid hydrocarbons will be liquid at room temperatureand atmospheric pressure, and will have a pour point in the range ofabout -40° C. and about 50° C., and a minimum boiling point not lessthan about 110° C. (atmospheric pressure). It is also known to utilizewaxy hydrocarbons, preferably having a melting point below about 100° C.The hydrocarbons constitute a preferred category of suds suppressor fordetergent compositions. Hydrocarbon suds suppressors are described, forexample, in U.S. Pat. No. 4,265,779, issued May 5, 1981 to Gandolfo etal. The hydrocarbons, thus, include aliphatic, alicyclic, aromatic, andheterocyclic saturated or unsaturated hydrocarbons having from about 12to about 70 carbon atoms. The term "paraffin," as used in this sudssuppressor discussion, is intended to include mixtures of true paraffinsand cyclic hydrocarbons.

Another preferred category of non-surfactant suds suppressors comprisessilicone suds suppressors. This category includes the use ofpolyorganosiloxane oils, such as polydimethylsiloxane, dispersions oremulsions of polyorganosiloxane oils or resins, and combinations ofpolyorganosiloxane with silica particles wherein the polyorganosiloxaneis chemisorbed or fused onto the silica. Silicone suds suppressors arewell known in the art and are, for example, disclosed in U.S. Pat. No.4,265,779, issued May 5, 1981 to Gandolfo et al and European PatentApplication No. 89307851.9, published Feb. 7, 1990, by Starch, M. S.

Other silicone suds suppressors are disclosed in U.S. Pat. No. 3,455,839which relates to compositions and processes for defoaming aqueoussolutions by incorporating therein small amounts of polydimethylsiloxanefluids.

Mixtures of silicone and silanated silica are described, for instance,in German Patent Application DOS 2,124,526. Silicone defoamers and sudscontrolling agents in granular detergent compositions are disclosed inU.S. Pat. No. 3,933,672, Bartolotta et al, and in U.S. Pat. No.4,652,392, Baginski et al, issued Mar. 24, 1987.

An exemplary silicone based suds suppressor for use herein is a sudssuppressing amount of a suds controlling agent consisting essentially of

(i) polydimethylsiloxane fluid having a viscosity of from about 20 cs.to about 1,500 cs. at 25° C.;

(ii) from about 5 to about 50 parts per 100 parts by weight of (i) ofsiloxane resin composed of (CH₃)₃ SiO_(1/2) units of SiO₂ units in aratio of from (CH₃)₃ SiO_(1/2) units and to SiO₂ units of from about0.6:1 to about 1.2:1; and

(iii) from about 1 to about 20 parts per 100 parts by weight of (i) of asolid silica gel.

In the preferred silicone suds suppressor used herein, the solvent for acontinuous phase is made up of certain polyethylene glycols orpolyethylene-polypropylene glycol copolymers or mixtures thereof(preferred), or polypropylene glycol. The primary silicone sudssuppressor is branched/crosslinked and preferably not linear.

To illustrate this point further, laundry detergent compositions withcontrolled suds will optionally comprise from about 0.001 to about 1,preferably from about 0.01 to about 0.7, most preferably from about 0.05to about 0.5, weight % of said silicone suds suppressor, which comprises(1) a nonaqueous emulsion of a primary antifoam agent which is a mixtureof (a) a polyorganosiloxane, (b) a resinous siloxane or a siliconeresin-producing silicone compound, (c) a finely divided filler material,and (d) a catalyst to promote the reaction of mixture components (a),(b) and (c), to form silanolates; (2) at least one nonionic siliconesurfactant; and (3) polyethylene glycol or a copolymer ofpolyethylene-polypropylene glycol having a solubility in water at roomtemperature of more than about 2 weight %; and without polypropyleneglycol. Similar amounts can be used in granular compositions, gels, etc.See also U.S. Pat. Nos. 4,978,471, Starch, issued Dec. 18, 1990, andU.S. Pat. Nos. 4,983,316, Starch, issued Jan. 8, 1991, 5,288,431, Huberet al., issued Feb. 22, 1994, and U.S. Pat. Nos. 4,639,489 and4,749,740, Aizawa et al at column 1, line 46 through column 4, line 35.

The silicone suds suppressor herein preferably comprises polyethyleneglycol and a copolymer of polyethylene glycol/polypropylene glycol, allhaving an average molecular weight of less than about 1,000, preferablybetween about 100 and 800. The polyethylene glycol andpolyethylene/polypropylene copolymers herein have a solubility in waterat room temperature of more than about 2 weight %, preferably more thanabout 5 weight %.

The preferred solvent herein is polyethylene glycol having an averagemolecular weight of less than about 1,000, more preferably between about100 and 800, most preferably between 200 and 400, and a copolymer ofpolyethylene glycol/polypropylene glycol, preferably PPG 200/PEG 300.Preferred is a weight ratio of between about 1:1 and 1:10, mostpreferably between 1:3 and 1:6, of polyethylene glycol:copolymer ofpolyethylene-polypropylene glycol.

The preferred silicone suds suppressors used herein do not containpolypropylene glycol, particularly of 4,000 molecular weight. They alsopreferably do not contain block copolymers of ethylene oxide andpropylene oxide, like PLURONIC L101.

Other suds suppressors useful herein comprise the secondary alcohols(e.g., 2-alkyl alkanols) and mixtures of such alcohols with siliconeoils, such as the silicones disclosed in U.S. Pat. Nos. 4,798,679,4,075,118 and EP 150,872. The secondary alcohols include the C₆ -C₁₆alkyl alcohols having a C₁ -C₁₆ chain. A preferred alcohol is 2-butyloctanol, which is available from Condea under the trademark ISOFOL 12.Mixtures of secondary alcohols are available under the trademarkISALCHEM 123 from Enichem. Mixed suds suppressors typically comprisemixtures of alcohol+silicone at a weight ratio of 1:5 to 5:1.

For any detergent compositions to be used in automatic laundry washingmachines, suds should not form to the extent that they overflow thewashing machine. Suds suppressors, when utilized, are preferably presentin a "suds suppressing amount." By "suds suppressing amount" is meantthat the formulator of the composition can select an amount of this sudscontrolling agent that will sufficiently control the suds to result in alow-sudsing laundry detergent for use in automatic laundry washingmachines.

The compositions herein will generally comprise from 0% to about 5% ofsuds suppressor. When utilized as suds suppressors, monocarboxylic fattyacids, and salts therein, will be present typically in amounts up toabout 5%, by weight, of the detergent composition. Preferably, fromabout 0.5% to about 3% of fatty monocarboxylate suds suppressor isutilized. Silicone suds suppressors are typically utilized in amounts upto about 2.0%, by weight, of the detergent composition, although higheramounts may be used. This upper limit is practical in nature, dueprimarily to concern with keeping costs minimized and effectiveness oflower amounts for effectively controlling sudsing. Preferably from about0.01% to about 1% of silicone suds suppressor is used, more preferablyfrom about 0.25% to about 0.5%. As used herein, these weight percentagevalues include any silica that may be utilized in combination withpolyorganosiloxane, as well as any adjunct materials that may beutilized. Monostearyl phosphate suds suppressors are generally utilizedin amounts ranging from about 0.1% to about 2%, by weight, of thecomposition. Hydrocarbon suds suppressors are typically utilized inamounts ranging from about 0.01% to about 5.0%, although higher levelscan be used. The alcohol suds suppressors are typically used at 0.2%-3%by weight of the finished compositions.

Fabric Softeners--Various through-the-wash fabric softeners, especiallythe impalpable smectite clays of U.S. Pat. No. 4,062,647, Storm andNirschl, issued Dec. 13, 1977, as well as other softener clays known inthe art, can optionally be used typically at levels of from about 0.5%to about 10% by weight in the present compositions to provide fabricsoftener benefits concurrently with fabric cleaning. Clay softeners canbe used in combination with amine and cationic softeners as disclosed,for example, in U.S. Pat. No. 4,375,416, Crisp et al, Mar. 1, 1983 andU.S. Pat. No. 4,291,071, Harris et al, issued Sep. 22, 1981.

Detersive Surfactants--Nonlimiting examples of surfactants which can beused herein in addition to the SAS particles, typically at levels fromabout 1% to about 55%, by weight, include the conventional C₁₁ -C₁₈alkyl benzene sulfonates ("LAS") and primary, branched-chain and randomC₁₀ -C₂₀ alkyl sulfates ("AS"), unsaturated sulfates such as oleylsulfate, the C₁₀ -C₁₈ alkyl alkoxy sulfates ("AE_(x) S"; especially EO1-7 ethoxy sulfates), C₁₀ -C₁₈ alkyl alkoxy carboxylates (especially theEO 1-5 ethoxycarboxylates), the C₁₀₋₁₈ glycerol ethers, the C₁₀ -C₁₈alkyl polyglycosides and their corresponding sulfated polyglycosides,and C₁₂ -C₁₈ alpha-sulfonated fatty acid esters. If desired, theconventional nonionic and amphoteric surfactants such as the C₁₂ -C₁₈alkyl ethoxylates ("AE") including the so-called narrow peaked alkylethoxylates and C₆ -C₁₂ alkyl phenol alkoxylates (especially ethoxylatesand mixed ethoxy/propoxy), C₁₂ -C₁₈ betaines and sulfobetaines("sultaines"), C₁₀ -C₁₈ amine oxides, and the like, can also be includedin the overall compositions. The C₁₀ -C₁₈ N-alkyl polyhydroxy fatty acidamides can also be used. Typical examples include the C₁₂ -C₁₈N-methylglucamides. See WO 9,206,154. Other sugar-derived surfactantsinclude the N-alkoxy polyhydroxy fatty acid amides, such as C₁₀ -C₁₈N-(3-methoxypropyl) glucamide. The N-propyl through N-hexyl C₁₂ -C₁₈glucamides can be used for low sudsing. C₁₀ -C₂₀ conventional soaps mayalso be used. If high sudsing is desired, the branched-chain C₁₀ -C₁₆soaps may be used. Mixtures of anionic and nonionic surfactants areespecially useful. Other conventional useful surfactants are listed instandard texts.

Other Ingredients--A wide variety of other ingredients useful indetergent compositions can be included in the compositions herein,including other active ingredients, carriers, processing aids, dyes orpigments, etc. If high sudsing is desired, suds boosters such as the C₁₀-C₁₆ alkanolamides can be incorporated into the compositions, typicallyat 1%-10% levels. The C₁₀ -C₁₄ monoethanol and diethanol amidesillustrate a typical class of such suds boosters. Use of such sudsboosters with high sudsing adjunct surfactants such as the amine oxides,betaines and sultaines noted above is also advantageous. If desired,soluble magnesium salts such as MgCl₂, MgSO₄, and the like, can be addedat levels of, typically, 0.1%-2%, to provide additional suds and toenhance grease removal performance.

Various detersive ingredients employed in the present compositionsoptionally can be further stabilized by absorbing said ingredients ontoa porous hydrophobic substrate, then coating said substrate with ahydrophobic coating. Preferably, the detersive ingredient is admixedwith a surfactant before being absorbed into the porous substrate. Inuse, the detersive ingredient is released from the substrate into theaqueous washing liquor, where it performs its intended detersivefunction.

To illustrate this technique in more detail, a porous hydrophobic silica(trademark SIPERNAT D10, DeGussa) is admixed with a proteolytic enzymesolution containing 3%-5% of C₁₃₋₁₅ ethoxylated alcohol (EO 7) nonionicsurfactant. Typically, the enzyme/surfactant solution is 2.5× the weightof silica. The resulting powder is dispersed with stirring in siliconeoil (various silicone oil viscosities in the range of 500-12,500 can beused). The resulting silicone oil dispersion is emulsified or otherwiseadded to the final detergent matrix. By this means, ingredients such asthe aforementioned enzymes, bleaches, bleach activators, bleachcatalysts, photoactivators, dyes, fluorescers, fabric conditioners andhydrolyzable surfactants can be "protected" for use in detergents.

The detergent compositions herein will preferably be formulated suchthat, during use in aqueous cleaning operations, the wash water willhave a pH of between about 6.5 and about 11, preferably between about7.5 and 11.0. Fabric laundry products are typically at pH 9-11.Techniques for controlling pH at recommended usage levels include theuse of buffers, alkalis, acids, etc., and are well known to thoseskilled in the art.

The following Examples illustrate the preparation and composition offree-flowing SAS particles which are prepared by the process of thisinvention. In Example II, the ingredient abbreviations refer to thefollowing materials: SAS (C14) and SAS (C16) are secondary (2,3) alkylsulfate surfactants with an average of 14 and 16 carbon atoms,respectively; C23AE6.5 is a C12-C13 alcohol ethoxylate surfactant withan average of 6.5 ethoxy units; C25AE9 is a C12-C15 alcohol ethoxylatesurfactant with an average of 9 ethoxy units; C45AE7 is a C14-C15alcohol ethoxylate surfactant with an average of 7 ethoxy units; thehydrophobic silica has a particle size in the range of from about 1 toabout 5 micrometers and is available as SIPERNAT D10 from Degussa; theZeolite A has a particle size in the 0.5-10 micrometer range; thebalance of the abbreviated ingredients are as defined hereinabove.

EXAMPLE 1

The following describes a procedure for preparing the SAS/Nonionicagglomerate particle herein using a pilot Lodige KM 50L batch mixer.

Step (a)--6,480 grams of the commercial C16 SAS powder and 1,560 gramsof commercial C14 SAS powder are mixed with 200 grams of powdered silicahaving a mean particle size of 1-5 micrometers in a Lodige KM 50L batchmixer for 130 seconds using 185 rpm and 3600 rpm blade and chopperrotation speeds, respectively.

Step (b)--The C45AE7 nonionic binder is heated to 65° C. 1,560 grams ofthis hot binder is sprayed onto the mixed powder of Step (a) in theLodige KM mixer using the maximum mixing speeds of the blade and thechopper for 190 seconds.

Step (c)--200 grams of dry, 1-10 micrometer sized, detergent gradeZeolite A is charged into the mixer and mixed for 70 seconds using 90rpm and 3600 rpm blade and chopper rotation speeds, respectively.

Step (d)--200 grams of the powdered silica is charged into the mixer andmixed for 70 seconds using 90 rpm and 3600 rpm blade and chopperrotation speeds, respectively.

Steps (c) and (d) are then repeated three more times. For the finalcoating step, 100 grams of powdered silica are added into the mixer andmixed for 70 seconds at 90 rpm and 3600 rpm blade and chopper rotationspeeds, respectively.

Step (e)--The final agglomerate is sieved through a #14 mesh Tylerscreen (1180 microns) to collect the desired particle size.

Using the procedure disclosed herein, soluble SAS particles are preparedas illustrated in Examples II A, B and C.

    ______________________________________    EXAMPLE II (A-C)                   % (Wt.)    Ingredient       A         B       C    ______________________________________    SAS(C16)         52.0      52.0    52.0    SAS(C14)         14.0      14.0    14.0    C23AE6.5         14.0      --      --    C25AE9           --        14.0    --    C45AE7           --        --      14.0    Zeolite A        9.0       9.0     9.0    Hydrophobic Silica                     4.0       4.0     4.0    Misc./Moist      7.0       7.0     7.0                     100.0     100.0   100.0    Physical Properties    Density (g/L)    659       677     681    Mean Particle Size (microns)                     634       607     636    ______________________________________

SAS particles prepared in the foregoing manner are free-flowing, havequite acceptable dusting and caking grades, and exhibit improvedsolubility over commercial SAS particles.

SAS particles prepared in the foregoing manner are used to providefully-formulated detergent compositions, as illustrated by thefollowing, non-limiting Examples. In Examples III-X, the overall weightpercent of the ingredients is listed in the vertical columns.

    __________________________________________________________________________    EXAMPLE III-X    Ingredient*              III IV  V   VI  VII VIII                                      IX  X    __________________________________________________________________________    Surfactants    C16 SAS   15.5                  8   8   8   16  10  5   7    C14 SAS   0   8   0   8   0   10  5   10    C18 SAS   0   5   7   0   0   0   5   0    C45 AS    18.4                  0   0   10  10  0   5   0    C45 AExS  0   0   3   0   0   0   0   0    Coconut AS              0   8   0   0   0   0   0   0    C12 LAS   11.1                  0   7   0   11  10  0   0    C13 LAS   0   0   5   0   0   0   5   0    C46 AOS   0   0   0   5   0   0   0   0    C68 ME5   0   10  0   5   0   0   10  15    C46 AGS   0   0   3   0   0   5   5   5    Hydroxyethyl mono-              1   0   0.5 0   1   0   1   1    dodecyl quat    Trimethyl alkyl    quat      0   1   0   0   0   0   0   0    Tallow soap              5   3   0   0   6   2   0   2    Coconut soap              0   2   0   0   0   0   0   0    Oleate soap              0   4   4   3   0   0   4   0    Neodol C45 E7              4   0   0   2   4.4 0   2   4    Neodol C23 E6.5              0   0   0   0   0   2   0   0    Neodol C25 E9              0   2.5 2   0   0   0   0   0    Coconut acyl              0   0   3   5   0   3   3   0    glucamide    Acyl monoethanol-              0   0   2   0   0   0   0   0    amide    Acyl diethanol-              0   0   0   2   0   0   0   0    amide    Salts/Builder    Layered silicate              4   0   0   15  5   0   18  20    Zeolite A 8   10  0   10  5   0   5   10    Zeolite X 0   0   15  0   0   7   0   0    Polyacrylate Na              8   0   10  0   2   1   0   5    Copolymer of              0   12  0   0   0   3   5   0    acrylate/maleate    NTA       0   0   0   0   5   0   0   0    STP       0   0   0   0   5   20  0   0    PEG 4000  1.9 0   1   2   1   1   2   2    Soda Ash  6   7   15  8   10  12  9   9    Powdered hydro-              0.5 1   0   1   0.8 1   1   1    phobic silica    sodium perborate              5   0   0   0   0   0   0   0    Sodium per-              0   5   0   0   5   0   0   0    carbonate    NOBS      4.5 2   0   0   5   0   0   0    TAED      0   3   0   0   0   0   0   0    Sodium sulfate              1   3   5   8   2   5   2   3    DTPA      0.5 0   0   0   0   0   0   0    EDDS      0   0   1   0   0   0   0   0    EDTA      0   0   0   1   0   0   0   0    Others    Perfume   0.3 0.3 0.3 0.2 0.2 0.2 0.3 0.2    Soil release              1   0   0   0   1   0   1   1    polymer    Brighteners              0.4 0.3 0.4 0   0.5 0.4 0.6 0.3    Polyvinyl Alcohol              0.1 0   0   2   0   0   0   0.2    or PVNO    Moisture  Balance    Total:    100 100 100 100 100 100 100 100    __________________________________________________________________________     *In the Examples IIIX, the abbreviations used for the Ingredients appear     hereinabove in the listing of Formulation Ingredients, or are as defined     hereinafter.     C45AExS is C.sub.14 -C.sub.15 alcohol ethoxylate (1-3) sulfate.     C46AOS is C.sub.14 -C.sub.16 alpha olefin sulfonate.     C68MES is C.sub.16 -C.sub.18 methyl ester sulfonate.     C46AGS is C.sub.14 -C.sub.16 alkyl glycerol sulfate.     Hydroxyethyl monododecyl quat is hydroxyethyl dodecyl dimethyl ammonium     chloride.     Trimethyl alkyl quat is dodecyl trimethyl ammonium chloride.     The NEODOLS are commercial nonionic surfactants.     Coconut acyl glucamide is coconutalkyl Nmethyl glucamide.     Acyl monoethanolamide is coconutalkyl monoethanolamide.     Acyl diethanolamide is coconutalkyl diethanolamide.     Layered silicate is SKS6.     Polyacrylate, Na has a molecular weight of 2000-6000.     Copolymer of acrylate/maleate has a molecular weight of 2000-20,000.     STP is sodium tripolyphosphate.     Soil release polymer is an anionic polyester; see Maldonado, Gosselink an     other patents cited above. METOLOSE, which is the trade name of methyl     cellulose ethers manufactured by Shinetsu Kagaku Kogyo K.K., and availabl     as METOLOSE SM15, SM100, SM200 and SM400, can be used.     Brighteners are TINOPALS ®, available from CibaGeigy.

The foregoing compositions are prepared by dry-blending the SASparticles herein with the balance of the ingredients. The compositionsare used as fabric laundry detergents, at conventional usage ranges fromabout 500 ppm to 20,000 ppm in aqueous media. The compositions exhibitexcellent cleaning performance and improved solubility, especially incompositions where the size of the SAS particles (i.e., largest diameterof the particles) is in the 100-2000 micrometer range. The C₁₆ SAS isespecially preferred.

What is claimed is:
 1. A process for preparing particles of secondary(2,3) alkyl sulfate surfactants with improved solubility, comprising thesteps of:(a) admixing said secondary (2,3) alkyl sulfate in particulateform with a de-agglomerating agent to provide a substantiallyhomogeneous powder mixture containing at least about 75%, by weight, ofsaid secondary (2,3) alkyl sulfate; (b) admixing a binding agent whichis a nonionic surfactant with the powder mixture from step (a) to formagglomerates; (c) admixing additional de-agglomerating agent to theagglomerates of step (b) until the size of said agglomerates is reducedto provide free-flowing particles in the mean size range of about 100 to2000 micrometers; (d) coating the particles of step (c) with a free-flowaid; and (e) optionally, sizing the coated particles of step (d) to amean particle size in the range from about 100 to about 1500micrometers.
 2. A process according to claim 1 wherein the homogeneouspowder mixture of step (a) comprises from about 75% to about 90%, byweight, of the secondary (2,3) alkyl sulfate surfactant.
 3. A processaccording to claim 1 wherein the deagglomerating agent in step (a) isselected from the group consisting of zeolites, silica, layeredsilicate, and mixtures thereof.
 4. A process according to claim 1,wherein the weight ratio of secondary (2,3) alkylsulfate:deagglomerating agent in step (a) is in the range from about80:20 to about 99.5:0.5.
 5. A process according to claim 1 wherein theweight ratio of secondary (2,3) alkyl sulfate to nonionic surfactant instep (b) is in the range from about 90:10 to about 75:25.
 6. A processaccording to claim 5 wherein the nonionic surfactant in step (b) is aC₁₄ -C₁₅ alcohol ethoxylate.
 7. A process according to claim 1 whereinthe free-flow aid in step (d) is selected from the group consisting offinely powdered zeolite, finely powdered silica and mixtures thereof. 8.A process according to claim 1 wherein the particles of step (d)comprise from about 5% to about 25%, by weight, of total zeolite andfrom about 0% to about 20%, by weight, of total silica.